1. Field of the Invention
The present invention relates broadly to friction liners and other mechanisms for enhancing a transfer of energy, in the form of, for example, torque and momentum, between a stator or other driver component and a rotor or other movable component. More particularly, the present invention concerns a micro-beam friction liner comprising a dense array of micro-beam projections having first ends substantially fixed relative to a rotor and second ends projecting substantially toward a plurality of teeth of a stator, wherein the micro-beam projections compress and bend to store energy during movement of the stator teeth and then react against the stator teeth to convert the stored energy to rotational energy in the rotor.
2. Description of the Prior Art
Generally, a piezoelectric material expands and contracts when an alternating voltage is applied across two opposing surfaces. In a rotary embodiment, a piezoelectric motor comprises a stator and a rotor, with the stator having a plurality of teeth that, due to a traveling wave developed in the stator by piezoelectric action, drives the rotor using elliptic motion of the stator teeth to transfer torque and momentum. Commonly, a friction liner is bonded to the rotor and the rotor and the friction liner are spring-loaded against the stator in order to maximize the transfer of torque and momentum therebetween.
Unfortunately, prior art friction liners are constructed of such materials as hard metals or metal oxides or soft organic polymers, and often experience slippage resulting in significant energy loss and reduced torque transfer. Furthermore, because the tangential velocity of each stator tooth varies at each point on its elliptical path, and because the rotor's velocity can be considered constant during one traversal of the ellipse, the tangential velocity of each stator tooth can only match the rotor velocity at one or two points along the elliptical path. Thus, the majority of contact between the stator tooth and the rotor or the friction liner involves slippage. Additionally, prior art friction liners typically have low Q, or little dynamic action. Such dynamic reaction force/impulse is thought to be one of the mechanisms whereby torque is transferred between the stator and the rotor.
Due to the above-identified and other problems and disadvantages in the art, a need exists for an improved friction liner.